It is well known to prepare epoxy compounds by reacting epihalohydrin with an active hydrogen-containing compound and subsequently dehydrohalogenating the chlorohydrin intermediate product with a basic acting compound such as an alkali or alkaline earth metal hydroxide or carbonate. Since epichlorohydrin is prepared in three steps from propylene (the very basic starting material) this entire process for the preparation of glycidyl ether (or other glycidyl derivative) based epoxy resins involves four or five steps depending upon whether or not steps four and five are conducted simultaneously or separately. The five-step reaction is as follows:
1) propylene+chlorine .fwdarw. allyl chloride PA1 2) allyl chloride+water+chlorine .fwdarw. dichloropropanol PA1 3) dichloropropanol+NaOH .fwdarw. epichlorohydrin PA1 4) epichlorohydrin+active hydrogen-containing compound such as a bisphenol .fwdarw. chlorohydrin intermediate PA1 5) chlorohydrin intermediate+basic acting compound .fwdarw. glycidyl ether epoxy resin PA1 (1) providing an allyl reagent which is substantially halogen-free and which reacts with an acid, hydroxyl or amine group to form an allyl ether, allyl thioether, allyl ester or allyl amine; PA1 (2) allylating one or more compounds containing at least one active hydrogen atom using the allyl reagent from step (1), whereby allyl ether, allyl thioether, allyl ester or allyl amine compound is formed; and PA1 (3) converting the allyl groups on the compound from step (2) to epoxide groups, whereby a glycidyl ether, glycidyl thioether, glycidyl ester or glycidyl amine compound is formed. PA1 1)Propylene+oxygen+acetic acid+catalyst .fwdarw. allyl acetate; PA1 2))Allyl acetate+active hydrogen-containing compound such as a bisphenol .fwdarw. diallyl derivative of active hydrogen-containing compound; and PA1 3)Diallyl derivative of active hydrogen-containing compound+peroxy oxidant .fwdarw. diglycidyl derivative of active hydrogen-containing compound. Although acetic acid is illustrated above to prepare allyl acetate which is employed as the allylating agent, it is understood that other acids and allylating agents as enumerated elsewhere herein can be employed in the process of the present invention. PA1 when a heterogeneous catalyst is employed by: PA1 when a homogeneous catalyst is employed by: PA1 1)Propylene+oxygen+acetic acid+catalyst .fwdarw. allyl acetate; PA1 2)Allyl acetate+active hydrogen-containing compound such as bisphenol-A .fwdarw. diallyl derivative of active hydrogen-containing compound; and PA1 3)Diallyl derivative of active hydrogen-containing compound+peroxy oxidant .fwdarw. diglycidyl derivative of active hydrogen-containing compound.
In the four-step reaction, steps four and five are conducted essentially simultaneously.
The most widely used current processes for the preparation of epichlorohydrin also produce a significant amount of chlorinated by-product such as 2-chloropropene, 2-chloropropane, allyl chloride, 1,2-dichloropropane, 3,3-dichloropropene, 2,3-dichloropropene, 1,3-dichloropropene, 1,3,3-trichloropropene, 1,2,3-trichloropropane, bis-(dichloropropyl)ethers, 2,3-dichloro-1-propanol, 1,3-dichloro-2-propanol. These by-products must be sold into a useful market or disposed of by environmentally friendly methods. Moreover, certain of the by-products are difficult to separate from the epihalohydrin. When the epihalohydrin is used to make epoxy resin, the epoxy resin becomes contaminated with undesirable bound and hydrolyzable halides resulting from reaction by-products and from incompletely reacted epihalohydrin.
What is needed is a process to make similar epoxy resins or other glycidyl compounds which process has one or more of the following advantages: fewer process steps, fewer halogenated by-products, and/or lower levels of halogenated contaminants, by-products, in the resulting resin or compound or simultaneously having an epoxide equivalent weight less than about 200 and an amount of total organic halide of less than about 200 ppm excluding any halogen atoms attached to an aromatic ring to which the group containing the vicinal epoxide group is attached.